Taplejung District is the Mountain district of Mechi Zone in Nepal's Eastern Development Region. The district covers 3,646 km2 (1,408 sq mi). The 2011 census counted 127,461 population. Taplejung is the district headquarters

The name Taplejung is derived from the words "Taple" and "jung". Taple was the medieval Limbu king who used to rule the area and "jung" in the Limbu language means fort. Literally, Taplejung means Fort of King Taple.